Commit 3dabe067 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Khalid Elmously

x86/apic: Soft disable APIC before initializing it

BugLink: https://bugs.launchpad.net/bugs/1848589

[ Upstream commit 2640da4c ]

If the APIC was already enabled on entry of setup_local_APIC() then
disabling it soft via the SPIV register makes a lot of sense.

That masks all LVT entries and brings it into a well defined state.

Otherwise previously enabled LVTs which are not touched in the setup
function stay unmasked and might surprise the just booting kernel.
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105219.068290579@linutronix.deSigned-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarConnor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
parent 39066500
......@@ -1266,6 +1266,14 @@ void setup_local_APIC(void)
return;
}
/*
* If this comes from kexec/kcrash the APIC might be enabled in
* SPIV. Soft disable it before doing further initialization.
*/
value = apic_read(APIC_SPIV);
value &= ~APIC_SPIV_APIC_ENABLED;
apic_write(APIC_SPIV, value);
#ifdef CONFIG_X86_32
/* Pound the ESR really hard over the head with a big hammer - mbligh */
if (lapic_is_integrated() && apic->disable_esr) {
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment